Such a head magnifier is known, for example, from U.S. Pat. No. 6,667,832 B2, wherein the adjusting mechanism comprises a rod on which a carrier with the magnifying optics fixed to it can be moved in a longitudinal direction. This has the disadvantageous effect that the rod protrudes forwardly with respect to the carrier in case of a minimal distance between the user's eyes and the magnifying optics. The length of this protruding portion of the rod corresponds substantially to the maximum distance between the magnifying optics and the user's eyes. Thus, a predetermined range of adjustment for the distance between the magnifying optics and the user's eyes always causes the rod to protrude forwardly with respect to the magnifying optics in an undesirable manner in those cases where the maximum distance between the magnifying optics and the user's eyes is not set.
In a head magnifier described in DE 28 02 940 C2 the swivel axis disadvantageously extends approximately in the middle between the front and the back of the head in the mounted condition of the head magnifier. Since the magnifying optics are arranged in front of the user's eyes, the swivel leverage and, thus, the torque caused by the magnifying optics is high. On the one hand, this is uncomfortable when wearing the head magnifier; on the other hand, a great mechanical effort is required in order to achieve precise swiveling and, thus, precise adjustment of the head magnifier to the user's corresponding viewing angle.